Japan Railway & Transport Review No. 63 (p26-p33) Feature : Maintenance of Railway Infrastructure (part 2) Maintenance and Management of JR East Civil Engineering Structures |
Introduction |
Japan’s problem of aging population and declining birth-rate has been known for years and the labour force, along with the general population, has been declining from the peak in 2005. With the declining workforce, no future increase in railway income not be expected, so limited resources must be used effectively to maintain and manage the social capital of railways. Social capital includes ground facilities, such as track, station, electrical, and train protection equipment. Track equipment is classified as rails, sleepers and ballast plus the civil engineering structures of roadbed, as well as bridges, tunnels, etc. This article describes the maintenance and management of civil engineering structures at JR East. |
Current State of Civil Engineering |
Major civil engineering structures in JR East’s business area include about 30,000 bridges (including viaducts), 1300 tunnels, and 5500 km of embankments and other earthworks (as of March 2013). Figure 1 shows the age of bridges and tunnels on conventional (narrow gauge) and shinkansen lines and their construction materials. Railway civil engineering structures were built before other existing social capital, and many constructed in the late 19th and early 20th centuries are still in service. For example, more than half of the bridges exceed the legally mandated service life stipulated by the Ministry of Finance ordinance (50 years for concrete bridges and 40 years for steel bridges). JR East’s oldest bridge is 127-year-old Mogami River Bridge (double Warren truss (pin jointed) through bridge) on the Aterazawa Line between Uzen-Nagasaki and Minami-Sagae. The oldest tunnel is the 126-year-old Shimizuyato Tunnel (brick arch and concrete internal wall)on the Tokaido main line between Hodogaya and Higashi-Totsuka. |
Photo: 127-year-old Mogami River Bridge Figure 1: Average Age of Civil Engineering Structures Photo: 126-year-old Shimizuyato Tunnel |
Maintenance and Management Cycle |
Detours and long-term service suspension are difficult for railways to accomplish, so maintenance and management has to be done quickly in the short time between trains. For that reason, civil engineering structures cannot be replaced like rails and overhead catenary. The basic concept is that even if a civil engineering structure has been in service for more than 100 years, its lifespan can be lengthened by appropriate inspections to find defects at an early stage, and dealing with those defects quickly. |
Inspections |
Civil engineering structures at JR East are inspected according to ministerial ordinance and internal criteria. Table 1 shows the type of inspections. The office personnel at local branches (structure maintenance offices) perform the actual inspections. |
Table 1: Inspection of Civil Engineering Structures Table 2: Judgement Classification of Civil Engineering Structures Figure 2: Maintenance Assistant System for Railway Structures Photo: Tunnel Lining Scanning Car (TuLIs) Photo: Peeling and flaking on concrete viaduct (top) After repair work (bottom) Photo: Concrete Lining Inspection Car (CLIC) Photo: Repaired concrete tunnel |
Case Examples of Measures Taken for Civil Engineering Structures |
Measures are taken according to the results of inspections to secure safe train operations. They include repair, improvement, replacement, restriction of use, and monitoring. In order to maintain functionality, JR East takes measures, such as repair and improvement of defects to prevent defects developing further, as well as replacement of some or all structural members. |
Photo: Secondary lining improvement of Tokyo Tunnel Photo: Replacement of Tone River Bridge |
Future Issues and Efforts |
About 40% of JR East’s personnel in charge of inspection work reach retirement age in the next 10 years. This rapid generation change is causing concern about a loss of or drop in inspection skills. Civil engineering structures in service are also getting older and new structures are being added as shinkansen lines are extended. In this situation, new technologies and methods are needed to maintain and increase levels of inspection skills and continue long-term use of the diverse mix of old and new civil engineering structures. |
Conclusion |
Railways have many types of civil engineering structures as their foundation, so many management resources (human and financial) are needed for maintenance and management, making this an important issue in managing a railway company. By actively introducing new technologies and techniques to detect defects earlier and more reliably permitting earlier and more effective countermeasures, JR East hopes to achieve efficient maintenance and management of civil engineering structures to support safe railway transportation that passengers can use with peace of mind. |
Tadayoshi Niitsu Mr Niitsu is a Deputy Manager of Facilities Department, Railway Operation Headquarters at East Japan Railway Company. |